It seems you have javascript errors on the page.
Check console in the browser and find out which script is causing issues.
Then you can try disable that plugin (or check with your theme).
That’s all what I can see -> link, and I still don’t know what to do with it
It seems there is a server-side PHP issue (error 500).
Try to check PHP error log to see which script caused the error.
If you are not familiar with WP/PHP you may need to ask your hosting company for help.
Please paste the error log here.
Once the script/code is identified we’ll know which plugin or theme caused the error.
Then we’ll check for the solution.
Are you still having issues?
I found literally nothing in logs. I have to ask my hosting provider.
OK. When you have some more information simply post it here.